1. Field of the Invention
This invention relates to feed horns for reflector antennas. More particularly, the invention relates to a cost effective and electrically optimized cross-polarization interference compensating feed horn for an offset reflector antenna arrangement.
2. Description of Related Art
Reflector antennas may be configured in an offset arrangement where a sub reflector and or feed is located spaced away from a center point of a reflector target beam path. Although offset reflector antenna geometry minimizes beam interference that would otherwise be generated by the presence of the subreflector and or feed, it also generates an inherent cross-polarization within the non-symmetric plane.
U.S. Pat. No. 6,771,225 discloses an elliptical main reflector and one piece feed horn in an offset configuration. The one piece feed horn is formed with compensation slots in a waveguide section that are open to the horn end of the feed, the slot depths limited and the innermost step face angled in an electrical performance compromise to enable manufacture via a single die casting.
In addition to the electrical performance compromises made to enable manufacture via a single die casting, U.S. Pat. No. 6,771,225 requires the manufacture of a separate embodiment for every desired combination of feed position/orientation, main reflector geometry and or operating frequency(s). The required complex die molds, unique to each embodiment, significantly increases tooling, manufacturing and inventory costs.
Competition within the reflector antenna industry has focused attention on antenna designs that reduce antenna production costs but which still satisfy and or improve upon stringent electrical specifications,
Therefore, it is an object of the invention to provide an apparatus that overcomes deficiencies in the prior art.